Dynamical Aspects in the Schwarzschild - De Sitter Geometry
| dc.contributor.advisor | Pacheco, Freitas (Professor) | |
| dc.contributor.author | Biressa, Tolu | |
| dc.date.accessioned | 2021-06-30T07:45:34Z | |
| dc.date.accessioned | 2023-11-09T11:26:37Z | |
| dc.date.available | 2021-06-30T07:45:34Z | |
| dc.date.available | 2023-11-09T11:26:37Z | |
| dc.date.issued | 2020-12-01 | |
| dc.description.abstract | Within the _CDM model, we studied dynamical aspects of the universe in SdS spacetime background. Mainly, the precession of orbits from solar-planetary to binary galaxy, the effect of geometry in radially falling particles to massive compacts and the gravitational deflection of light by extended sources. Using Einstein field equations and conservation laws, equation of motion and the general effective potential in SdS were derived. The potential has used in the characterization of the orbits, where hypothetical potential sources ranging from small mass to critical black holes were used. The sample orbiters cover both massive and massless particles with and without angular momentum. Generally, SdS potential differs from the Schwarzschild potential. Moreover, the potential has used to derive important boundary conditions in the motion of the particles. Specially, it has used to derive photon orbit and radial solution of closed circular orbits of massive particles. Taking into account the positions of the source, lens and observer the photon orbit solution used to derive the gravitational bending angle; where it has in turn used in gravitational lensing to estimate the mass of the lensing where _ effect was of order 2% relative to the Schwarzschild background. In the case of circular orbits, the radial deviation has studied, where the effect was insignificant at small-scale, within Milky-Way galaxy; but at binary galaxy level becomes viable, kpc to Mpc order. For the case of elliptical orbits, a two-body problem has developed to derive the precession. _ effect was dominant over the Schwarzschild in open and wide systems like binary galaxy, but insignificant in others. _ has significant effect compared to the Schwarzschild case on radiations from in falling particles to massive objects if appreciable distances are considered. Finally, we have reflected our views regarding the criticisms on Einstein modified field equations, attributed to the cosmological constant. A detailed review with some supplementary works presented to enrich the relevance of the cosmological constant as an intrinsic constant. | en_US |
| dc.identifier.uri | http://10.90.10.223:4000/handle/123456789/27013 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Cdm Model | en_US |
| dc.subject | Sds | en_US |
| dc.subject | Cosmological Constant | en_US |
| dc.subject | Orbit Precession | en_US |
| dc.subject | Light Bending | en_US |
| dc.subject | Lensing | en_US |
| dc.subject | Gr | en_US |
| dc.title | Dynamical Aspects in the Schwarzschild - De Sitter Geometry | en_US |
| dc.type | Thesis | en_US |